Safety heel ski binding

ABSTRACT

A step-in safety heel ski binding wherein a heel-holding link is movable by the ski boot from a raised position to a lower position and is moved into engagement with parts fixed to the ski in a first intermediate position which is nearer to the lower position than a second intermediate position in which the link is released from such parts on forcible movement from lower position toward raised position. A spring is stressed during movement of the link from raised position to first intermediate position and biases the link from first intermediate position to lower position.

United States Patent Willy Suhner Aarauerstr. 38, Brugg, Switzerland [21] Appl. No. 836,840

[72] Inventor [22] Filed June 26, 1969 [45] Patented May 11, 1971 [32] Priority Nov. 14, 1968 [33] Switzerland [31] 16998/68 [54] SAFETY HEEL SKI BINDING 21 Claims, 9 Drawing Figs.

[52] US. Cl 280/11.35T [51] Int. Cl A63c 9/00 [50] Field ofSearch 280/11.35

[56] References Cited UNITED STATES PATENTS 3,351,354 11/1967 Smolka et al. 280/1 1.35HA

3,366,394 l/ 1968 Shimizn 3,432,180 3/1969 Suhner Primary Examiner-Benjamin Hersh Assistant Examiner-Robert R. Song AttomeyMichael S. Striker ABSTRACT: A step-in safety heel ski binding wherein a heelholding link is movable by the ski boot from a raised position to a lower position and is moved into engagement with parts fixed to the ski in a first intermediate position which is nearer to the lower position than a-second intermediate position in which the link is released from such parts on forcible movement from lower position toward raised position. A spring is stressed during movement of the link from raised position to first intermediate position and biases the link from first intermediate position to lower position.

. Patented Ma 11, 1971 3,578,350

5 Sheets-Sheet 1 Patented May 11, 1971 5 Sheets-Sheet 3 Patented May 11, 1971 3,578,350

5 sheets-Sh t 5 M-FI-Tw INVENTOR.

SAFETY nEEL sxr BINDING BACKGROUND OF THE INVENTION The present invention relates to safety heel ski bindings in general, and more particularly to improvements in step-in safety heel ski bindings.

It is already known to construct a safety heel ski binding in such a way that the heel-holding part of the binding is moved into engagement with parts fastened to the ski by the ski boot whereby the boot tensions a spring, and that the heel-holding part is disengaged from such parts in response to exertion of a predetermined force which tends to move the heel away from the adjoining portion of the ski. Such force develops when the skier is involved in an accident.

A drawback of presently known safety heel ski bindings is that their retaining (clamping) action is not reproducible with a requisite degree of accuracy as well as that such clamping action depends too much on the presence or absence of compacted snow or ice between the sole of the boot and the adjoining part of the ski. The clamping action also depends on the magnitude of variable frictional forces, on the presence or absence of lubricant between the movable parts of the binding, on the presence or absence of foreign matter in the joints between relatively movable parts, and on certain other factors. As a rule, the resistance of the binding to movement of the heel-holding part to disengaged position increases with prolonged use so that the likelihood of injury also increases.

Another serious drawback of presently known safety heel ski bindings is that the position of the heel-holding part at the moment of engagement with parts fastened to the ski is identical with or very close to the position which such part assumes when it is disengaged from such parts. This is undesirable for a variety of reasons, for example, because a layer of compacted snow or ice which happens to be present between the sole of the boot and the adjoining portion of the ski might compel the heel-holding part to assume a position which is very close to the position of disengagement from parts fastened to the ski. Consequently, a very small force in a direction to move the heel away from the ski suffices to permit disengagement of the boot which can cause serious accidents, not only because the skier loses his or her balance but also because the retaining action is too unstable.

Otherwise stated, in a diagram showing the retaining force as a function of the upward movement of the heel, the differential quotient of such curve in the neighborhood of the snap point (where said force has the value zero) is relatively low. The just described drawbacks are characteristic of many conventional bindings wherein a knee-lever is used as engaging mechanism.

SUMMARY OF THE INVENTION An object of the invention is to provide a relatively simple, inexpensive, compact and reliable step-in safety heel ski binding which overcomes the drawbacks of aforediscussed conventional ski bindings.

Another object of the invention is to provide a ski binding which is constructed in such a way that, once the heel-holding part is moved into engagement with parts fastened to the ski, the skier knows that a certain minimum upward movement of the heel is needed to free the heel and to permit disengagement of the boot from the binding.

Still another object of the invention is to provide novel means for establishing and terminating an elastic connection between the heel-engaging member and parts which'are connected to the ski.

A further object of the invention is to provide a ski binding which is more versatile than presently known ski bindings and which can be used not only for skiing on slopes but also for walking with skis without interfering with movements of the skiers legs.

An additional object of the invention is to provide a ski binding which can be manipulated by grownups or children and which can be adjusted to insure satisfactory engagement with boots of different types, with boots used by heavier or lighter skiers, as well as by advanced skiers or beginners.

The invention is embodied in a step-in safety heel ski binding which I prefer to call hysteresis binding and which comprises a linkage including supporting means arranged to be secured to a ski and a heel-holding member which is movably carried by the supporting means and is movable by a ski boot from a raised or inoperative position through a first intermediate position in which it is moved into engagement with parts fastened to the ski, and onto a lower or operative position, and biasing means for urging the heel-holding member to lower position when the member reaches the first intermediate position during movement from raised position. The biasing means offers to the heel-holding member a greater resistance during movement from lower position to a second intermediate position and a lesser resistance (including no resistance at all) during movement from the second intermediate position to raised position. The distance between the first intermediate and lower positions of the heel-holding member is substantially or noticeably less than the distance between the second intermediate and lower positions. This provides for a safety margin because the heel-holding member is properly engaged when it is moved well below the position in which it can be disengaged from the heel. The arrangement is preferably such that the biasing means opposes movement of the heel-holding member from lower position to second intermediate position.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved safety heel ski binding itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic side elevational view of the linkage in a step-in safety heel ski binding which embodies the invention;

FIG. 2 is an enlarged longitudinal vertical sectional view of the ski binding in open position;

FIG. 3 is a similar view of the ski binding in operative position;

FIG. 4 is a similar view of the ski binding in a third position;

FIG. 5 is a smaller-scale perspective view of the ski binding in the position corresponding to that shown in FIG. 3;

FIG. 6 is a perspective view of the binding in a position its parts assume during attachment to the heel of a ski boot; and

FIG. 7 is a plan view of an actuating member in the ski binding.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The safety ski binding of the present invention comprises a linkage which is shown schematically in FIG. 1. It comprises a supporting link 1 which can be secured to a ski or to a plate which is mounted on the ski, a front link 2, a rear link 3, a lower link 4, an upper link 5, and a heel-holding link 6. Each of the links 1, 4 and 5 comprises two sections (see FIGS. 2, 3 and 4) and the sections of links 4, 5 are turnable about common pivot axes defined by pivot members respectively provided on links 3, 6 and 2, 3, 6. The links 2, 3 are pivoted to the link 1 and the pivot for the rear end of the link 4 is located between the pivots at the ends of the link 3. The fact that some of the links comprise pairs of sections is of no consequence for proper operation of the improved safety binding.

The operative or lower end position of the heel-holding link 6 is shown in FIG. 3 by solid lines. When the link 6 is thereupon moved to its raised or upper end position or inoperative position (FIG. 2), it initially shares pivotal movement of the heel 7a on the ski boot 7 and thereupon moves along a different arcuate path so that it becomes separated from the heel 7a. This renders it possible to introduce the boot 7 into the safety binding in the upper end position of the link 6 (FIG. 2) and to automatically move the link 6 to the lower end position of FIG. 3 in response to depression of a pedal 8 which is located below the underside of the boot 7 in the region of the heel 7a and forms part of or is attached to the link 6. When the pedal 8 is depressed, the link 6 moves into engagement with the heel 7a and thereupon remains in engagement with the heel while the pedal 8 continues to move downwardly toward the lower end position shown in FIG. 3. Spring means may be interposed between the ski 9 and the supporting link 1 to enhance engagement between the link 6 and heel 7a.

A biasing element 10 (here shown as a helical spring) is installed between the links and 6. However, such mounting of the spring is optional because it can be mounted between another pair of links, and it is equally possible to employ two or more springs. Depending on its mounting, the spring 10 can be an expansion spring or a contraction spring. The spring 10 may accommodate or it may be accommodated in a further spring. A feature of the present invention resides in that the spring 10 is mounted in such a way and at such location that it is caused to store energy by way of a transmission so that the maximum distance covered by the heel 7a to move the link 6 from the raised position to the first intermediate position exceeds the distance which is necessary to cause the spring to store energy. Otherwise, the force (namely, a portion of the weight of the person using the ski 9) would not suffice to insure storage of energy by a spring which is strong enough for the purposes of the present invention. The transmission ratio is preferably more than two-to-one and not less than l.5:l, most preferably 2.5:1. The distance which the link 6 must cover during stressing of the spring 10 is preferably at least twice the difference between the lengths of spring 10 in stressed and unstressed conditions.

In the embodiment which is illustrated in the drawing, one end of the spring 10 bears against a portion of the link 6 by way of a lower retainer 11 and the lower end of a spindle l4, and acts on this link in the general direction of movement of the link from the raised position of FIG. 2 to the lower end position of FIG. 3. This is the presently preferred mounting of the spring 10.

Prior to downward movement of the link 6 from the raised position shown in FIG. 2, the spring 10 is held (preferably in prestressed condition) between the lower retainer 11 and an upper retainer 12. The lower retainer 11 has a tapped bore and meshes with the externally threaded portion 13 of the spindle 14. The upper retainer 12 is slidable along a smooth portion of the spindle l4 and its upward movement is limited by the head 15 of the spindle. This head is preferably slotted or of noncircular outline so that it can be readily engaged and rotated by a screwdriver, wrench or other simple tool. The lower end of the spindle 14 is coupled to a socket 120 which is free to swivel in a hole 16 of the link 6. The axis of the spindle 14 is located in the longitudinal vertical symmetry plane of the binding.

A pivot member 17 on the link 5 carries a bistable actuating lever 18 which is biased by a spring 19 and tends to assume one of two end positions with reference to the link 5. The lower one of these positions of the actuating lever 18 is shown in FIG. 2. The movement of lever 18 to such lower end position can be brought about by a ski pole (not shown) whose tip is insertable into an opening or recess 20 whereby a certain pressure upon the pole suffices to pivot the lever 18 to illustrated position. The lever 18 has two actuating portionsor cams 21 which consequently share its movements with the link 5. A torsion spring 22 is provided to bias the upper retainer 12 for the spring 10 in a direction toward the link 6, namely, in the direction of forward movement of the ski 9. The torsion spring 22 extends into notches 23 provided therefor in the retainer 12.

When the skier places the underside of the boot 7 onto the pedal 8 and pushes the pedal downwardly, the cams 21 of the actuating lever 18 press against the upper side of the retainer 12 in response to angular movement of the link 5 and lever 18 and cause the retainer 12 to travel downwardly along the smooth portion of the spindle 14 to thereby stress the spring 10.

The supporting link 1 carries two-armed locking levers 24 each of which can be pivoted slightly beyond the illustrated position in a clockwise direction but not anticlockwise. These locking levers have suitably inclined guide faces 25. While the boot 7 pushes the pedal 8 downwardly and causes the link 6 to move from the raised position of FIG. 2 toward the lower end position of FIG. 3, the faces 26 of the upper retainer 12 engage the guide faces 25 of the locking levers 24. The inclination of the faces 26 is such that the retainer 12 is caused to move rearwardly against the opposition of the torsion spring 22. This causes the retainer 12 to move with reference to the cams 21 of the actuating lever 18 until the cams 21 enter the notches 23 and snap into such notches to set free the retainer 12 in the position shown in FIG. 3. The spring 10 is then free to dissipate some energy and to propel the retainer 12 upwardly until the projections 27 of the retainer 12 engage locking projections 28 of the levers 2.4. This is the operative position of the safety binding in which the heel-engaging link 6 is in engagement with parts fastened to the ski 9 in requisite position for skiing. At such time, the link 6 is no more subjected to any upwardly directed stresses. The spring 10 presses the link 6, and hence the heel 7a of the boot 7 (by way of a portion 29 of the link 6), against the ski 9 or against a layer of compacted snow or ice on the upper surface of the ski. The portion 29 is preferably adjustable with reference to the remainder of the heel-engaging link 6 in the axial direction of an adjusting bolt 29a. Once the portion 29 is properly adjusted in accordance with the thickness of the heel, its position with reference to the remainder of the link 6 remains unchanged. The above-described snapping action takes place suddenly under the action of the spring 10 when the link 6 reaches the first intermediate position. If the thickness of the layer of compacted snow or ice below the heel 7a of the boot 7 is excessive, the link 6 cannot be propelled all the way to the first intermediate position and the person wearing the boot 7 immediately notes that the safety binding is not ready for use. The just described construction prevents the parts of the binding from assuming an undesirable and potentially dangerous unstable position in which the heel 7a would not be held at all or would be held in a position in which a minimal upward displacement of the rear portion of the boot 7 would suffice to disengage the binding.

FIG. 3 shows that the spring 10 tends to move the retainer 12 (and hence the projections 27) in a direction to pivot the locking levers 24 in a clockwise direction and to thereby terminate engagement between the locking levers 24 and the retainer 12. Such disengagement is normally prevented by engagement of stop faces 30 on the lower arms of lockin levers 24 with complementary retaining or blocking faces 31 on the pedal 8 of the link 6. Thus, as long as the blocking faces 31 register with and remain adjacent to the stop faces 30, the locking levers 24 cannot pivot in a clockwise direction and thus prevent disengagement of the heel-engaging portion 29 from the boot 7.

In the event of an accident, i.e., when the skier falls forwardly so that the rear portion of the boot 7 moves upwardly and away from the adjoining portion of the ski 9, the portion 29 causes the link 6 to move away from the ski and to stress the spring 10. Such stressing is terminated when the portion 29 reaches the phantom-line position 29' of FIG. 3. In such position of the portion 29, the blocking faces 31 of the pedal 8 are lifted above and away from the stop faces 30 of the locking levers 24 so that these levers are free to pivot in a clockwise direction and to move their projections 28 away from the projections 27 of the upper retainer 12. The spring 10 propels the retainer 12 against the head 15 of the spindle 14 so that the bias of the spring 10 is taken up only by the spindle, i.e., by the head 15 and by the lower retainer 11 which is rigid with the threaded portion 13. This relieves the skiers leg of excessive stresses but the heel of the foot is still guided against lateral movement until the heel 7a of the boot 7 is lifted sufficiently to cause a pivotal movement of the heel-engaging link 6 away from the boot.

The improved safety binding releases the boot 7 suddenly as soon as the blocking faces 31 move away from registry with the stop faces 30. The locking levers 24 are then immediately propelled to positions of disengagement from the upper retainer 12 and the latter is immediately propelled against the head 15 to permit practically unobstructed movement of the link 6 away from the ski 9. That (second intermediate) position of the link 6, in which the latter is disengaged from the parts fastened to the ski 9 (namely, from the levers 24) is determined by the height of stop faces 30 and blocking faces 31. It is clear that such position of disengagement of stop faces 30 from the blocking faces 31 must be selected in such a way that it is located at a level above the (first intermediate) position in which the spring 10 causes the projections 27 of the retainer 12 to engage the projections 28 of the locking levers 24. Thus, the stop faces 30 and blocking faces 31 must be located opposite each other when the projections 27 engage the projections 28. Such construction of the binding is desirable because it insures that the boot 7 is properly and safely held in requisite position even if the layer of compacted snow or ice between the ski 9 and boot 7 is so high that the binding is barely capable of assuming its operative position. In other words, there is always a safety margin so that a properly engaged heel 7a must cover a certain minimum distance away from the ski 9 before the link 6 is disengaged.

The initial stressing of the spring 10 can be regulated by rotating the spindle 14 through the intermediary of the head 15. This enables the skier to properly relate the bias of the spring 10 to his or her weight. The lower retainer 11 is guided by the link 6 in such a way that it can not rotate with the spindle 14 so that, when the spindle is rotated by way of the head 15, the retainer 11 is compelled to move up or down and to thus change the initial stressing of the spring 10.

If the skier wishes to disengage the safety binding, i.e., when the disengagement is to take place intentionally rather than as a result of an accident, the ring of a ski pole can be used to pivot the actuating lever 18 to its upper end position. This causes the cams 21 of the lever 18 to move to the dotted positions 21" of FIG. 3 and to thereby push the upper retainer 12 forwardly in order to disengage the projections 27 from the projections 28 of the locking levers 24. The spring 10 is then free to expand and the boot 7 can be readily removed from the binding. In order to insure that the link 6 can move to the raised position of FIG. 2, the lever 18 should be returned to its lower end position as soon as the projections 27 are disengaged from the projections 28.

The improved safety heel binding is further suited to be used for walking on snow, i.e., for movements when the heel 7a moves up and down with reference to the adjoining portion of the ski 9. This is achieved by moving the actuating lever 18 to the upper position. As stated before, the projections 27 are then disengaged from the projections 28 so that the spring 10 expands and frees the heel 7a for limited movement toward and away from the adjoining portion of the ski 9. The cams 21 remain in the notches 23 (in positions 21"). The extent of movement of the heel 7a is limited to a lower section of the path of the link 6 whereby the link shares the movement of the heel of the boot. The extent of the just described movement is preferably limited by yieldable resilient means. As shown, the lower link 4 has extensions 32 which project through openings 33 into the interior of the binding and engage edge faces 34 on arms 35 forming part of a rocker 36 which is pivotally connected with the actuating lever 18. The rocker 36 then pivots in a counterclockwise direction and thereby stresses the spring 19. The positions of edge faces 34 are selected in such a way that they can be engaged by the extensions 32 only when the lever 18 is moved to upper end position. In the lower end position of this lever (i.e., when the lever 18 is in the position shown in FIG. 3), the extensions 32 are free to bypass the edge faces 34 so that the link 6 can move all the way to the raised position shown in FIG. 2.

It is clear that the improved safety binding is susceptible of many additional modifications without departing from the spirit of the present invention. For example, the binding may be provided with a single locking lever 24, a single notch 23, a single cam 21, a single projection 27, a single extension 32 and/or a single arm 35. Moreover, the actuating lever 18 can be replaced by a slide (i.e., by a reciprocable actuating member). Furthermore, the positions of notches 23 and cams 21 can be reversed.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended.

I claim:

1. In a step-in safety heel ski binding, a combination comprising at least one part mounted on the ski; a linkage including supporting means arranged secured to the ski and a heelholding member movably carried by said supporting means and being movable by a ski boot from a raised position through a first intermediate position, in which it is moved into engagement with said part, and to a lower position; and deformable biasing means for urging said heel-holding member to lower position when said member reaches the first intermediate position during movement from raised position, said biasing means offering to said heel-holding member a greater resistance during movement from lower position to a second intermediate position and a lesser resistance during movement from said second intermediate position to raised position, the distance between said first intermediate and lower positions being substantially less than the distance between said second intermediate and lower positions.

2. A combination as defined in claim 1, wherein said biasing means comprises spring means whose length varies in response to deformation thereof and wherein the distance between said raised and lower positions of said member exceeds the maximum change in length of said spring means by at least 50 percent.

3. A combination as defined in claim 2, wherein said distance is more than twice said maximum change in length.

4. A combination as defined in claim 1, wherein said heelholding member comprises a heel-engaging portion which remains in engagement with the heel during movement of said member from lower to second member intermediate position and moves away from the heel during movement of said member from second intermediate to raised position.

5. A combination as defined in claim 1, further comprising means for stressing said biasing means during a portion of movement of said heel-holding member from raised to lower position, the distance covered by said member during said portion of its movement being less than half the distance between said raised and lower positions.

6. A combination as defined in claim 1, wherein said part mounted on the ski comprises further locking means against which said biasing means reacts in the lower position of said heel-holding member so that said biasing means opposes movement of said member from lower position.

7. A combination as defined in claim 1, further comprising means for regulating the initial stress of said biasing means.

8. A combination as defined in claim 1, wherein said part mounted on the ski comprises locking means having a first portion arranged to releasably hold said biasing means in stressed condition so that the biasing means opposes movement of said heel-holding member from lower position and a second portion which permits said first portion to release said biasing means on movement of said member from lower position to said second intermediate position.

9. A combination as defined in claim 8, wherein said locking means comprises a lever pivotally mounted on said supporting means and having first and second arms which are respectively provided with said first and second portions.

10. A combination as defined in claim 9, further comprising blocking means for holding said lever against pivotal movement in a direction to release said biasing means while said member remains at a level below said second intermediate position.

11. A combination as defined in claim 10, wherein said blocking means is provided on said heel-holding member.

12. A combination as defined in claim 1, wherein said linkage further comprises a link pivotable with reference to said heel-holding member and arranged to stress said biasing means during movement of said member from raised position to said first intermediate position thereof, said part mounted on the ski comprising locking means provided on said supporting means and operative to take up the stress of said biasing means in the first intermediate position of said member so that the biasing means thereupon urges said member toward lower position, and blocking means for holding said locking means in operative position during movement of said member from lower position to said second intermediate position against the opposition of said biasing means whereby said biasing means is thereupon free to propel the heel-holding member toward raised position.

13. A combination as defined in claim 1, wherein said linkage further comprises a link pivotally connected with said heel-holding member and cam means carried by said link and arranged to stress said biasing means during movement of said member from raised position to said first intermediate position, and further comprising a retainer movable with reference to said heel-holding member and interposed between said cam means and said biasing means, said part mounted on the ski including locking means movably secured to said supporting means and arranged to engage said retainer on completed movement of said member from raised position to first intermediate position, and blocking means for holding said locking means in engagement with said retainer during movements of said member from lower position to said second intermediate position.

14. A combination as defined in claim 13, further comprising means for adjustably securing said cam means to said link.

15. A combination as defined in claim 14, wherein the means for adjustably securing said cam means to said link comprises an actuating lever and further comprising resilient means for permanently urging said lever to one of two end positions with reference to said link.

16. A combination as defined in claim 15, wherein said retainer has a notch which receives said cam means in a first end position of said actuating lever in the lower position of said heel-holding member.

17. A combination as defined in claim 16, a further comprising rocker means movably mounted on said lever and having a portion engaging a second link of said linkage in the second end position of said lever.

18. A combination as defined in claim 1, wherein said biasing means comprises at least one prestressed spring which operates between said member and a link of said linkage and biases said member during a portion of movement of said member between raised and lower positions.

19. A combination as defined in claim 1, further comprising transmission means for stressing said biasing means during a portion of movement of said member from raised to lower position.

20. A combination as defined in claim 19, wherein the distance between said raised and lower positions is at least 152 times the distance covered by said member during said portion of its movement.

21. A combination as defined in claim 1, further comprising actuating means operative to effect disengagement of said member from the heel and locking means for holding said member in lower position by way of said biasing means, said actuating means being operative to disengage sad part mounted on the ski from said member. 

1. In a step-in safety heel ski binding, a combination comprising at least one part mounted on the ski; a linkage including supporting means arranged secured to the ski and a heel-holding member movably carried by said supporting means and being movable by a ski boot from a raised position through a first intermediate position, in which it is moved into engagement with said part, and to a lower position; and deformable biasing means for urging said heel-holding member to lower position when said member reaches the first intermediate position during movement from raised position, said biasing means offering to said heel-holding member a greater resistance during movement from lower position to a second intermediate position and a lesser resistance during movement from said second intermediate position to raiseD position, the distance between said first intermediate and lower positions being substantially less than the distance between said second intermediate and lower positions.
 2. A combination as defined in claim 1, wherein said biasing means comprises spring means whose length varies in response to deformation thereof and wherein the distance between said raised and lower positions of said member exceeds the maximum change in length of said spring means by at least 50 percent.
 3. A combination as defined in claim 2, wherein said distance is more than twice said maximum change in length.
 4. A combination as defined in claim 1, wherein said heel-holding member comprises a heel-engaging portion which remains in engagement with the heel during movement of said member from lower to second member intermediate position and moves away from the heel during movement of said member from second intermediate to raised position.
 5. A combination as defined in claim 1, further comprising means for stressing said biasing means during a portion of movement of said heel-holding member from raised to lower position, the distance covered by said member during said portion of its movement being less than half the distance between said raised and lower positions.
 6. A combination as defined in claim 1, wherein said part mounted on the ski comprises further locking means against which said biasing means reacts in the lower position of said heel-holding member so that said biasing means opposes movement of said member from lower position.
 7. A combination as defined in claim 1, further comprising means for regulating the initial stress of said biasing means.
 8. A combination as defined in claim 1, wherein said part mounted on the ski comprises locking means having a first portion arranged to releasably hold said biasing means in stressed condition so that the biasing means opposes movement of said heel-holding member from lower position and a second portion which permits said first portion to release said biasing means on movement of said member from lower position to said second intermediate position.
 9. A combination as defined in claim 8, wherein said locking means comprises a lever pivotally mounted on said supporting means and having first and second arms which are respectively provided with said first and second portions.
 10. A combination as defined in claim 9, further comprising blocking means for holding said lever against pivotal movement in a direction to release said biasing means while said member remains at a level below said second intermediate position.
 11. A combination as defined in claim 10, wherein said blocking means is provided on said heel-holding member.
 12. A combination as defined in claim 1, wherein said linkage further comprises a link pivotable with reference to said heel-holding member and arranged to stress said biasing means during movement of said member from raised position to said first intermediate position thereof, said part mounted on the ski comprising locking means provided on said supporting means and operative to take up the stress of said biasing means in the first intermediate position of said member so that the biasing means thereupon urges said member toward lower position, and blocking means for holding said locking means in operative position during movement of said member from lower position to said second intermediate position against the opposition of said biasing means whereby said biasing means is thereupon free to propel the heel-holding member toward raised position.
 13. A combination as defined in claim 1, wherein said linkage further comprises a link pivotally connected with said heel-holding member and cam means carried by said link and arranged to stress said biasing means during movement of said member from raised position to said first intermediate position, and further comprising a retainer movable with reference to said heel-holding member and interposed between said Cam means and said biasing means, said part mounted on the ski including locking means movably secured to said supporting means and arranged to engage said retainer on completed movement of said member from raised position to first intermediate position, and blocking means for holding said locking means in engagement with said retainer during movements of said member from lower position to said second intermediate position.
 14. A combination as defined in claim 13, further comprising means for adjustably securing said cam means to said link.
 15. A combination as defined in claim 14, wherein the means for adjustably securing said cam means to said link comprises an actuating lever and further comprising resilient means for permanently urging said lever to one of two end positions with reference to said link.
 16. A combination as defined in claim 15, wherein said retainer has a notch which receives said cam means in a first end position of said actuating lever in the lower position of said heel-holding member.
 17. A combination as defined in claim 16, a further comprising rocker means movably mounted on said lever and having a portion engaging a second link of said linkage in the second end position of said lever.
 18. A combination as defined in claim 1, wherein said biasing means comprises at least one prestressed spring which operates between said member and a link of said linkage and biases said member during a portion of movement of said member between raised and lower positions.
 19. A combination as defined in claim 1, further comprising transmission means for stressing said biasing means during a portion of movement of said member from raised to lower position.
 20. A combination as defined in claim 19, wherein the distance between said raised and lower positions is at least 1 1/2 times the distance covered by said member during said portion of its movement.
 21. A combination as defined in claim 1, further comprising actuating means operative to effect disengagement of said member from the heel and locking means for holding said member in lower position by way of said biasing means, said actuating means being operative to disengage said part mounted on the ski from said member. 